Cavities are areas in the hard surface of your teeth that are damaged. These areas of tooth decay become tiny openings or holes that can lead to a serious toothache, infection and tooth loss. There are several causes of cavities, including bacteria in your mouth, snacking a lot, sipping sugary drinks and not cleaning your teeth well.

Cavities and tooth decay are among the world's most common health problems. They're especially common in children, teenagers and older adults. But anyone who has teeth can get cavities, including babies.

If cavities aren't treated, they get larger and affect deeper layers of your teeth. Regular dental visits and good brushing and flossing habits are the best ways to protect your teeth from cavities.


The symptoms of cavities vary, depending on how many you have and where they're located. When a cavity is just beginning, you may not have any symptoms. As the decay gets larger, it may cause symptoms such as:

  • Toothache and other pain.
  • Tooth sensitivity.
  • Mild to sharp pain when eating or drinking something sweet, hot or cold.
  • Holes or pits in your teeth that you can see.
  • Brown, black or white staining on any surface of a tooth.
  • Pain when you bite down.

When to see a dentist

You may not be aware that a cavity is forming. That's why it's important to have regular dental checkups and cleanings, even when your mouth feels fine. But if you have a toothache or mouth pain, see your dentist as soon as possible.


Tooth decay causes cavities. This is a process that occurs over time.

Here's how tooth decay happens:

  • Plaque forms. Dental plaque is a clear sticky film that coats your teeth. It's due to eating a lot of sugars and starches and not cleaning your teeth well. When you don't clean sugars and starches off your teeth, bacteria quickly begin feeding on them and forming plaque. Plaque that stays on your teeth can harden under or above your gumline into tartar. Tartar makes plaque harder to remove and creates a shield for bacteria. A dental professional needs to remove this plaque.
  • Plaque attacks. The acids from bacteria remove minerals in your tooth's hard, outer enamel. This erosion causes tiny openings or holes in the enamel — the first stage of cavities. Once areas of enamel are worn away, the bacteria and acid can reach the next layer of your teeth, called dentin. This layer is softer than enamel and less resistant to acid, causing your teeth to be more sensitive.
  • Damage continues. As tooth decay happens, the bacteria and acid move through your teeth to the inner tooth material (pulp) that contains nerves and blood vessels. The pulp becomes swollen and irritated from the bacteria. Because there is no place for the swelling to expand inside of a tooth, the nerve becomes pressed, causing pain. Sometimes pain and damage can spread outside of the tooth root to the bone, causing bone loss around the tooth and even reaching nearby teeth.

Risk factors

Anyone who has teeth can get cavities, but these factors raise the risk:

  • Tooth location. Decay most often occurs in your back teeth — your molars and premolars. These teeth have lots of grooves, pits and crannies, and multiple roots that can collect food particles. That's why they're harder to keep clean than your smoother, easy-to-reach front teeth.
  • Certain foods and drinks. Foods that cling to your teeth for a long time are more likely to cause decay than foods that are easily washed away by saliva. These foods include milk, ice cream, honey, sugar, soda, dried fruit, cake, cookies, hard candy and mints, dry cereal, and chips.
  • Snacking or sipping a lot. When you snack or sip sugary drinks a lot, you give mouth bacteria more fuel to make acids that attack your teeth and wear them down. And sipping soda or other acidic drinks throughout the day helps create a continual acid bath over your teeth.
  • Bedtime baby feeding. When babies are given bedtime bottles filled with milk, formula, juice or other liquids that have sugar, these beverages remain on their teeth for hours while they sleep. This feeds bacteria that can cause decay. This damage often is called baby bottle tooth decay. Similar damage can occur when toddlers wander around drinking from a sippy cup filled with these beverages.
  • Not brushing your teeth well. If you don't clean your teeth soon after eating and drinking, plaque forms quickly, and the first stages of decay and gingivitis can begin.
  • Not getting enough fluoride. Fluoride, a naturally occurring mineral, helps prevent cavities. It also can reverse the earliest stages of tooth damage. Because of its benefits for teeth, fluoride is added to many public water supplies. It's also a common ingredient in toothpaste and mouth rinses. But bottled water usually does not contain fluoride.
  • Younger or older age. In the U.S., cavities are common in very young children and teenagers. Older adults also are at higher risk. Over time, teeth can wear down and gums may recede, making teeth more likely to decay. Older adults also may use more medicines that reduce saliva flow, raising the risk of tooth decay.
  • Dry mouth. Dry mouth is caused by a lack of saliva. Saliva helps prevent tooth decay by washing away food and plaque from your teeth. Substances found in saliva also help counter the acid produced by bacteria. Certain medicines, some medical conditions, radiation to your head or neck, or certain chemotherapy drugs can raise your risk of cavities by reducing saliva production.
  • Worn fillings or dental devices. Over the years, dental fillings can weaken, begin to break down or get rough edges. This allows plaque to build up more easily and makes it harder to remove. Dental devices can stop fitting well, allowing decay to begin under them.
  • Heartburn. Heartburn, a common symptom of gastroesophageal reflux disease (GERD), can cause stomach acid to flow into your mouth. This is called reflux. It can wear away the enamel of your teeth and cause a lot of damage. This exposes more of the dentin to bacteria, creating tooth decay. Your dentist may recommend that you talk with your healthcare professional to see if GERD is causing your enamel loss.
  • Eating disorders. Anorexia and bulimia can lead to a lot of tooth erosion and cavities. Stomach acid from repeated vomiting, called purging, washes over the teeth and begins eating away at the enamel. Eating disorders also can get in the way of saliva production.


Cavities and tooth decay are so common that you may not take them seriously. And you may think that it doesn't matter if children get cavities in their baby teeth. But cavities and tooth decay can have serious and lasting complications, even for children who don't have their permanent teeth yet.

Complications of cavities may include:

  • Pain.
  • Abscess — a bacterial infection that causes a pocket of pus to form in a tooth.
  • Swelling or pus around a tooth.
  • Damage or broken teeth.
  • Chewing problems.
  • Positioning shifts of teeth after tooth loss.

When cavities and decay become serious, you may have:

  • Pain that makes it hard to live your daily life.
  • Weight loss or nutrition problems because it's painful or difficult to eat or chew.
  • Tooth loss, which may affect your appearance, confidence and self-esteem.
  • In rare cases, a tooth abscess, which can lead to more-serious or even life-threatening infections.


Good oral and dental hygiene can help keep you from getting cavities. Here are some tips to help prevent cavities. Ask your dentist which tips are best for you.

  • Brush with fluoride toothpaste after eating or drinking. Brush your teeth at least twice a day, and ideally after every meal, using toothpaste with fluoride. To clean between your teeth, floss or use an interdental cleaner. This cleaner helps reach areas where a toothbrush can't reach.
  • Rinse your mouth. If your dentist feels that you have a high risk of getting cavities, a mouth rinse with fluoride may be recommended.
  • Visit your dentist regularly. Get professional teeth cleanings and regular oral exams, which can help prevent problems or spot them early. Your dentist can recommend a schedule that's best for you.
  • Consider dental sealants. A sealant is a protective plastic coating applied to the chewing surface of back teeth. It seals off grooves and crannies that tend to collect food, protecting tooth enamel from plaque and acid. The Centers for Disease Control and Prevention recommends sealants for all school-age children. Sealants may last for several years before they need to be replaced, but they need to be checked regularly.
  • Drink some tap water. Most public water supplies have added fluoride, which can reduce tooth decay greatly. If you drink only bottled water that doesn't contain fluoride, you'll miss out on the benefits of fluoride.
  • Avoid snacking and sipping a lot. Whenever you eat or drink beverages other than water, you help your mouth bacteria create acids that can destroy tooth enamel. If you snack or drink throughout the day, your teeth are under constant attack.
  • Eat tooth-healthy foods. Some foods and beverages are better for your teeth than others. Avoid foods that get stuck in grooves and pits of your teeth for long periods, or brush soon after eating them. Foods such as fresh fruits and vegetables increase saliva flow, and unsweetened coffee, tea and sugar-free gum help wash away food particles.
  • Consider fluoride treatments. Your dentist may recommend periodic fluoride treatments, especially if you aren't getting enough fluoride through fluoridated drinking water and other sources. Your dentist also may recommend custom trays that fit over your teeth to apply prescription fluoride if your risk of tooth decay is very high.
  • Ask about antiseptic and disinfecting treatments. If tooth decay is likely — for example, because of a medical condition — your dentist may recommend special antiseptic and disinfecting mouth rinses like chlorhexidine or other treatments to cut down on harmful bacteria in your mouth. Unless your dentist tells you otherwise, mouth rinses, also called mouthwash, generally are not recommended for children younger than the age of 6 so they don't swallow too much of it.
  • Combined treatments. Chewing sugar-free gum along with prescription fluoride and an antibacterial rinse can help reduce the risk of cavities. But in some people, xylitol, which is often found in sugar-free gum or sugar-free candies, may cause gas or diarrhea if consumed in large amounts.